Regarding Gush Katif, I don't think people on the forum understand that the failure had nothing to do with whether it was a rightwinger or a leftwinger pushing the policy. The failure was the ideology of most people in Gush Katif which largely said that any Israeli policy is supreme (even above Torah, or in their mind it really is compatable with Torah but you just can't understand how). It was not a delusion that they thought it was a good policy, or unwillingness to oppose the policy or to oppose right or oppose left, because sharon's such a great guy, it was an unwillingness to fight the establishment, period. Gush Katif was mostly filled with mamlachtim and also secular Jews. Those mamlachtim unwilling to fight sabotaged the efforts of those who were willing to fight the establishment. Whether right or left, same result. If it was livni or some other pathetic leftwinger they still would have been weak-kneed in saying "no" to the Israeli establishment.
I believe that a big part of the difference with Amona was that people learned the lessons from Gush Katif, saw what mistakes were made, and took a different path. This included but not limited to, those who showed up to defend filling the place with people really willing to fight (not mamlachtim), keeping the yesha council out of it for the most part, and no big opportunity for erev rav to sabotage from within as it was less centralized and less under a given authority.
Those are my two cents, what say ye, Chaim?